CVE-2026-41210: CWE-787: Out-of-bounds Write in moonlight-stream moonlight-qt
Description
Moonlight Qt is a GameStream client for Windows, macOS, Linux, and Steam Link. In version 6.1.0 and earlier, after a victim initiates a streaming session to a malicious host, the host can send a crafted H.264 SPS NAL when Moonlight selects a decoder path that does not advertise CAPABILITY_REFERENCE_FRAME_INVALIDATION_AVC. The SPS fixup path in app/streaming/video/ffmpeg.cpp parses the server-provided data with h264bitstream, where attacker-controlled seq_parameter_set_id is used to index the 32-entry sps_table without validation. A value of 32 or greater causes an out-of-bounds write and remote heap corruption in the Moonlight client. The demonstrated impact is a reliable client crash, while code execution is not established. This issue is fixed in version 6.2.0.
CVSS v3.1
Score 6.5medium
Affected software
moonlight-stream
moonlight-qt
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-18T02:51:52.975Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6acd52432cdf04f656d94f15
Added to database: 10/12/2026, 21:33:55 UTC
Last updated: 10/12/2026, 21:33:55 UTC
Views: 1
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